Ask someone what the longest vehicular tunnel in Michigan is, they'll probably say the Detroit-Windsor tunnel. But we share that tunnel with Canada.

At 5150 feet long, it's certainly a long tunnel - just shy of a mile. So what's the longest tunnel that's entirely in Michigan? You have to go to Michigan's airports. There is are two tunnels along John Dingell Drive at Detroit Metro airport, one just shy of 1000 feet the other is around 1500 feet. In the West Michigan city of Holland you'll find the longest tunnel on the west side of the state. Drive south of town on Washington Street and you'll pass through a tunnel that carries the street under a runway at the West Michigan Regional Airport, perhaps better known by its former name, Tulip City Airport.

The South Washington Street tunnel is just 887 feet, or 0.18 of a mile. So if you're travelling along South Washington, there's a chance that there's an airplane taxiing on runway 8/26.

The image above is the look heading northbound. Here's the southbound entrance to the tunnel:

Google Maps Street View

There aren't any other vehicular tunnels to be found in the state. There are railway tunnels, one connecting Detroit-Windsor and another between Port Huron and Sarnia, the St Clair Tunnel.